This disclosure relates to the selection and delivery of online content.
Online content can include web pages and advertisements displayed with the web pages. Content publishers have space that they sell to advertisers or other content providers directly or through intermediaries. Some of a publisher's available space may be sold through a content inventory marketplace. This content inventory market may be a spot market that connects publishers with content providers (e.g., advertisers) in response to a request for content from a user. The publisher may communicate with one or more content providers or market intermediaries in an attempt to sell the space.